During the past decade there has been an exponential growth in the number, scope and complexity of catheter-based interventions for structural heart disease. Transcatheter aortic valve replacement (TAVR), endovascular aneurysm repair (EVAR), vena caval filters and intracardiac defect closure are all well developed and growing treatment strategies. The recent FDA approval of left atrial appendage (LAA) occlusion for atrial fibrillation and patent foramen ovale (PFO) closure for cryptogenic stroke, has opened the door for the high volume application of these procedures. The trend shows signs of acceleration with ever more complex therapeutic options on the horizon including devices for transcatheter mitral replacement (TMVR). Currently remedial surgical procedures are required to retrieve misplaced devices. A transcatheter retrieval system would represent a major advance that would spare patients the pain of remedial surgical procedures and provide a ?safety net? that promotes the use of these less invasive procedures and expands the number of patients who benefit from them. Our group has begun development of such retrieval system. The system consists of (1) customized co- axial catheter for introduction of the system and recovery of the target implant, (2) a novel nitinol wire woven basket designed to envelope, compress and retrieve the target implant, (3) mechanical advantage system for steady application of the withdraw force and (4) manipulation tools to aid in orienting the target implant. In preliminary work we have demonstrated the effectiveness of the basket in compressing large stents (aortic valve frames, aortic aneurysm stents). The feasibility of introducing early prototypes into the heart and withdrawing them in animal models has also been shown. Since the last submission of this application, studies of initial prototypes have identified weakness in the design which have been improved significantly. The goal of the current Phase I STTR proposal is to strengthen the existing proof of principle data and justify the further optimization of the design and implementation of the Onocor Retrieval system.